Can you believe that the largest hot desert in the world was once covered in luscious vegetation?! Well it's true, and it was not a 'one off' event. Actually, the Sahara Desert has been green many times in Earth's history. It has also occasionally been covered in water or ice! In this video, I talk about the history of the African continent with respect to its geographical movement through plate tectonics and it's associated climate as it moved up and down in latitude, with a special focus on the Sahara region.
Africa, and most of the modern continents today, were smushed together in the supercontinent Gondwana in the Precambrian about 500 to 300 million years ago. During its time in Gondwana, Africa was covered with Ice and/or water due to Gondwana's southern position. When Gondwana and Laurentia (the other, more northern landmass at the time) collided to form the supercontinent, Pangea, Africa was right in the middle of this collision. This meant mountain building along it's margins and increasing aridity (or drying) during its time in Pangea (around 300-200 million years ago) due to the large land area away from any ocean margin. Eventually, Pangea broke up (around 200 to 65 million years ago) and the Mediterranean Sea formed. Around 6 to 5.3 million years ago, the Messinian Salinity Crisis resulted from a major drying and evaporation event of the Mediterranean Sea. Even after this major drying event, however, the Sahara desert had another major 'green' period around 11,700 years ago in which it became covered in vegetation! This Green Sahara event ended about 5,000 years ago when rain patterns changed drying out the Sahara region once again.

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References: Earth System History book: https://amzn.to/3v1Iy0G
Ancient Supercontinents & Paleogeography book: https://amzn.to/44Q6jKS
Watrin et al., 2009: Plant migration and plant communities at the time of the “green Sahara”- https://doi.org/10.1016/j.crte.2009.0...
Tierney et al., 2017: Rainfall regimes of the Green Sahara- https://doi.org/10.1126/sciadv.1601503
Hely et al., 2009: Climate and vegetation: Simulating the African humid period- https://doi.org/10.1016/j.crte.2009.0...
deMenocal & Tierney, 2012: Green Sahara: African Humid Periods Paced by Earth’s Orbital Change- https://www.nature.com/scitable/knowl...

0:00 Ice-covered Sahara ~500-360 Ma
1:48 Sea & Forest-covered Sahara ~360-300 Ma
2:32 Drying Sahara before Great Dying ~300-250 Ma
3:14 Mediterranean Sea formation
3:52 East African Rift formation
4:19 When the Mediterranean Sea dried up
5:48 How Milankovitch cycles affect the Sahara
6:49 How the Ice Age affects the Sahara
7:32 “Green Sahara”
8:05 Desertification of the Sahara
9:37 How the Sahara maintains the Amazon!

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Non-textbook books I recommend:
Oxygen by D. Canfield: https://amzn.to/3gffbCL
Brief history of Earth by A. Knoll: https://amzn.to/3w3hC1I
Life on young planet by A. Knoll: https://amzn.to/2RBMpny
Some assembly required by N. Shubin: https://amzn.to/3w1Ezm2
Your inner fish by N. Shubin: https://amzn.to/3cpw3Wb
Oxygen by N. Lane: https://amzn.to/3z4FgwZ
Alien Oceans by K. Hand: https://amzn.to/3clMx1l
Life's Engines: https://amzn.to/3w1Nhke

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Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!